Developer container, developing device, process cartridge and image forming apparatus

ABSTRACT

A developer container includes a frame, provided with an opening, for accommodating a developer; a sealing member, including a folded-back portion, for sealing the opening; and a sandwiching portion for sandwiching the folded-back portion of the sealing member. In a plane perpendicular to the opening, the sealing member is nonwelded in the sandwiching portion.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a developer container, a developingdevice, a process cartridge and an image forming apparatus.

Here, the developer container is a container for accommodating adeveloper carrying member, for visualizing an electrostatic latent imagewith the developer. Further, the developer container is used alone so asto be detachably mountable to the image forming apparatus.

Further, the process cartridge refers to a cartridge constituted byintegrally assembling at least the developer container and the developercarrying member into a unit, which is detachably mountable to an imageforming apparatus main assembly.

Examples of the image forming apparatus may include anelectrophotographic copying machine, an electrophotographic printer(such as an LED printer or a laser beam printer) and anelectrophotographic facsimile machine, in which an image is formed on arecording material (medium) by using an electrophotographic imageforming process.

In the image forming apparatus using the electrophotographic imageforming process, a process cartridge type in which anelectrophotographic photosensitive drum and a process means actable onthe drum into a cartridge (unit), which is detachably mountable to theimage forming apparatus main assembly is employed. According to thisprocess cartridge type, maintenance of the apparatus can be performed bya user himself (herself) without relying on a service person, andtherefore operativity was able to be considerably improved. For thatreason, this process cartridge type has widely been used in the imageforming apparatuses.

Such a process cartridge includes a developer accommodating portion foraccommodating a toner as the developer for visualizing a latent imageformed on the photosensitive drum and a developing unit including adeveloping means for developing the latent image with the toner. Duringa brand-new state of the process cartridge including the developingunit, a toner sealing member for preventing the developer in thedeveloper accommodating portion from entering a developing unit sidethrough an opening provided in the developer accommodating portion isprovided. For that reason, when the user uses the process cartridge, theuser peels off the toner sealing member from the process cartridge andthen mounts the process cartridge in the image forming apparatus mainassembly.

Further, in recent years, from the viewpoint of usability, aconstitution in which the toner sealing member is peeled off only bymounting the process cartridge into the image forming apparatus mainassembly is disclosed (Japanese Laid-Open Patent Application (JP-A) Hei5-197288 and JP-A 2014-66967). In this constitution, one end portion ofthe toner sealing member is mounted on a rotatable member in thedeveloper accommodating portion and the toner sealing member isautomatically wound up around the rotatable member with drive of theimage forming apparatus main assembly, so that the toner can be sent tothe developing unit.

However, in the constitution in which the toner sealing member providedon the opening of the toner accommodating portion is pulled byrotational drive of the image forming apparatus main assembly, there wasa problem that a torque when the toner sealing member was pulled waslarge. This is because when the toner sealing member is pulled, a forcefor peeling off a welded portion between the developer accommodatingportion and the toner sealing member is needed. The welded portion isportion where an adhesive layer is provided on the toner sealing memberand then heated and welted at the opening of the developer accommodatingportion and thus is bonded to a periphery of the opening, so that theopening is completely closed (blocked) using the welded portion and thustoner leakage is prevented. However, from the viewpoints of energysaving and downsizing in recent years, there arose a need to reduce thetorque, when the toner sealing member was pulled, to the possibleextent.

SUMMARY OF THE INVENTION

A principal object of the present invention is to reduce a torque when atoner sealing member is pulled while preventing toner leakage from adeveloper accommodating portion before a user uses an image formingapparatus.

According to an aspect of the present invention, there is provided adeveloper container comprising: a frame, provided with an opening, foraccommodating a developer; a sealing member, including a folded-backportion, for sealing the opening; and a sandwiching portion forsandwiching the folded-back portion of the sealing member, wherein in aplane perpendicular to the opening, the sealing member is nonwelded inthe sandwiching portion.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1, (a) and (b) are sectional views of a developing device unitaccording to Embodiment 1.

FIG. 2 is a sectional view of an image forming apparatus in Embodiment1.

FIG. 3 is a sectional view of a cartridge in Embodiment 1.

FIG. 4 is a perspective view showing a state in which the cartridge isbeing mounted into the image forming apparatus in Embodiment 1.

FIG. 5 is a perspective view of the cartridge in Embodiment 1.

In FIG. 6, (a) and (b) are perspective views each showing a stirringmember in Embodiment 1.

In FIG. 7, (a) and (b) are perspective views for illustrating assemblingof a sealing member in Embodiment 1.

In FIG. 8, (a) to (d) are sectional views for illustrating an unsealingoperation of the sealing member in Embodiment 1.

In FIG. 9, (a) and (b) are illustrations each showing a toner fillingport in the developing device unit in Embodiment 1.

In FIG. 10, (a) is an illustration of a toner supply opening inEmbodiment 1, and (b) is a graph showing a result of comparison andinvestigation of a torque during unsealing of a sealing member inEmbodiment 1 and Comparison Example.

In FIG. 11, (a) and (b) are sectional views of a developing device unitaccording to Embodiment 2.

In FIG. 12, (a) and (b) are schematic views for illustrating asandwiching portion in Embodiment 2.

FIG. 13 is a graph showing a result of comparison and investigation of atorque during unsealing of a sealing member in Embodiment 2 andComparison Example.

In FIG. 14, (a) to (c) are sectional views of a developing device unitaccording to Embodiment 3.

FIG. 15 is a graph showing a result of comparison and investigation of atorque during unsealing of a sealing member in Embodiment 3 andComparison Example.

In FIG. 16, (a) to (c) are sectional views of another developing deviceunit in Embodiment 3.

In FIG. 17, (a) and (b) are sectional views of a developing device unitaccording to Embodiment 4.

FIG. 18 is a graph showing a result of comparison and investigation of atorque during unsealing of a sealing member in Embodiment 4 andComparison Examples 1 and 2.

In FIG. 19, (a) and (b) are sectional views of a developing device unitaccording to Embodiment 5.

FIG. 20 is a graph showing a result of comparison and investigation of atorque during unsealing of a sealing member in Embodiment 5 andComparison Examples 1 and 2.

In FIG. 21, (a) and (b) are sectional views of a developing device unitaccording to Embodiment 6.

FIG. 22 is a graph showing a result of comparison and investigation of atorque during unsealing of a sealing member in Embodiment 6 andComparison Examples 1 and 2.

DESCRIPTION OF THE EMBODIMENTS

Embodiments for carrying out the present invention will be specificallydescribed with reference to the drawings. Dimensions, materials, shapesand relative arrangement of constituent elements described in thefollowing embodiment should be appropriately be changed depending onstructures and various conditions of devices (apparatuses) to which thepresent invention is applied. Accordingly, the scope of the presentinvention is not intended to be limited to the following embodiments.

[Embodiment 1]

An image forming apparatus to which a cartridge according to thisembodiment is detachably mountable will be described. In thisembodiment, as the image forming apparatus, a laser beam printer usingelectrophotography will be described as an example.

(Structure of Image Forming Apparatus)

In FIG. 2, the image forming apparatus in this embodiment is the laserbeam printer, using the electrophotography, in which a cartridge B isdetachably mountable to an apparatus main assembly A. When the cartridgeB is mounted in the apparatus main assembly A, above the cartridge B, anexposure device 3 (laser scanner unit) is provided. Further, below thecartridge B, a sheet tray 4 in which a recording material (sheetmaterial P) to be subjected to image formation is accommodated isprovided.

Further, in the apparatus main assembly A, along a feeding direction Dof the sheet material P, a pick-up roller 5 a, a feeding roller pair 5b, conveying roller pairs 5 c, a transfer guide 6, a transfer roller 7,a conveying guide 8, a fixing device 9, a discharging roller pair 10, adischarge tray 11 and the like are successively provided. Incidentally,the fixing device 9 is constituted by a heating roller 9 a and apressing roller 9 b.

(Image Forming Process Operation)

Next, the image forming process will be described using FIGS. 2 and 3.On the basis of a print start signal, an electrophotographicphotosensitive drum 62 is rotationally driven at a predeterminedperipheral speed (process speed: 215 mm/sec) in an arrow R direction inFIG. 2. A charging roller 66 to which a charging bias voltage is appliedcontacts an outer peripheral surface of the drum 62 and electricallycharges the outer peripheral surface of the drum 62 uniformly. Theexposure device 3 outputs laser light L depending on image information.The laser light L passes through an exposure window portion 74 providedat an upper surface of the cartridge B, so that the outer peripheralsurface of the drum 62 is subjected to scanning exposure. As a result,on the outer peripheral surface of the drum 62, an electrostatic latentimage depending on the image information is formed.

On the other hand, as shown in a sectional view of the cartridge in FIG.3, in a developing device unit 20 as a developing device, a toner T in atoner chamber 29 is stirred and fed by rotation of a rotatable member45, so that the toner T is sent to a toner supplying chamber 28. Thetoner T is carried by a magnetic force of a magnet roller 34 (fixedmagnet) on a surface of a developing roller (developer carrying member)32. The toner T is regulated in layer thickness on the peripheralsurface of the developing roller 32 by a developing blade 42 while beingtriboelectrically charged. The toner T is transferred onto the drum 62depending on the electrostatic latent image, so that the electrostaticlatent image is visualized as a toner image which is a developer image.

Further, as shown in FIG. 2, in synchronism with output timing of thelaser light L, by the pick-up roller 5 a, the feeding roller pair 5 band the conveying roller pair 5 c, the sheet material P accommodated ata lower portion of the apparatus main assembly A is fed from the sheettray 4. The sheet material P is supplied to a transfer position betweenthe drum 62 and the transfer roller 7 via the transfer guide 6. In thistransfer position, the toner image is successively transferred from thedrum 62 onto the sheet material P. The sheet material P on which thetoner image is transferred is separated from the drum 62 and then isconveyed to the fixing device 9 along the conveying guide 8. Then, thesheet material P passes through a fixing nip between the heating roller9 a and the pressing roller 9 b which constitute the fixing device 9. Atthis fixing nip, pressure and heat fixing is effected, so that the tonerimage is fixed on the sheet material P. The sheet material P on whichthe toner image is fixed is conveyed to the discharging roller pair 10and then is discharged onto the discharge tray 11.

On the other hand, as shown in FIG. 3, the drum 62 after the transferis, after a residual toner on the outer peripheral surface of the drum62 is removed by a cleaning blade 77, used again in the image formingprocess. The residual toner removed from the drum 62 is stored in aresidual toner chamber 71 b of a cleaning unit 60.

(Mounting and Demounting Constitution of Cartridge)

Next, mounting and demounting of the cartridge B relative to theapparatus main assembly A will be described using FIG. 4. FIG. 4 is aperspective view of the apparatus main assembly in which an openabledoor 13 is opened for mounting and demounting the cartridge B, and ofthe cartridge B.

The apparatus main assembly is provided with the openable door 13 so asto be rotatable. When the openable door 13 is opened, a guide rail 12 isin sight, and the cartridge B is mounted into the apparatus mainassembly A along the guide rail 12. Then, a driving shaft 14 driven by amotor (not shown) of the apparatus main assembly A engages with adriving force receiving portion provided on the cartridge B. As aresult, the drum 62 connecting with the driving force receiving portionreceives the driving force from the apparatus main assembly A, and thusis rotated.

(General Structure of Process Cartridge)

Next, with reference to FIGS. 3 and 5, a general structure of thecartridge B will be described. FIG. 5 is a perspective view forillustrating a structure of the cartridge B.

The cartridge B is constituted by combining the cleaning unit 60 and thedeveloping device unit 20. The cleaning unit 60 is constituted by acleaning frame 71, the drum (first bearing member) 62, the chargingroller 66, the cleaning blade 77 and the like. On the other hand, thedeveloping device unit 20 is constituted by, a cap member 22, a toneraccommodating frame 23, first and second side members 26L and 26R, adeveloping blade 42, the developing roller 32, the magnet roller 34, atoner stirring sheet 44, the toner T, an urging member 46, and the like.These cleaning unit 60 and developing device unit 20 are rotationallymovably connected with each other by a connecting member 75, so that thecartridge B is constituted.

Specifically, at free end portions of arm portions 26aL, 26aR formed onthe first and second side members 26L, 26R provided at both end portionsof the developing device unit 20 with respect to a longitudinaldirection of the developing device unit 20, rotational movement holes26bL, 26bR in parallel with the developing roller 32 are provided,respectively. Further, at each of longitudinal end portions of thecleaning frame 71, an engaging hole 71 a for permitting engagementtherein of the connecting member 75 is formed.

Then, the arm portions 26aL and 26aR are aligned with predeterminedpositions of the cleaning frame 71, and then the connecting members 75are inserted into the rotational movement holes 26bL and 26bR and theengaging holes 71 a. As a result, the cleaning unit 60 and thedeveloping device unit 20 are connected with each other rotatably aboutthe connecting members 75.

At this time, urging members 46 mounted at base portions of the armportions 26aL and 26aR abut against the cleaning frame 71, so that theurging members 46 urge the developing device unit 20 toward the cleaningunit 60 with the connecting members 75 as the rotation centers. As aresult, the developing roller 32 is pressed toward the drum 62 withreliability.

(Developing Device Unit)

Next, the developing device unit in the present invention will bedescribed. First, using FIG. 6, a constitution of a rotatable memberunit 54 used in the present invention will be described.

As shown in 8 a) of FIG. 6, the rotatable member unit 54 is constitutedby a sealing member (toner sealing member) 52, the toner stirring sheet44 and the rotatable member 45. The sealing member 52 is constituted bya material compatible with a material of the toner accommodating frame23 or by a material including an adhesive layer. In this embodiment, asthe material of the sealing member 52, a material, such as PET, PC orPPS, which has flexibility and which includes the adhesive layer capableof being melted by heat and bonded to a frame (container) 23. Thesealing member 52 is provided with a plurality of holes 52 a arranged ina longitudinal direction, of the rotatable member 45, which is an axialdirection of the rotatable member 45.

The toner storing sheet 44 as a stirring member is formed with asheet-shaped material, such as PET, PC or PPS, having flexibility, andis provided with a plurality of holes 44 a arranged in the longitudinaldirection of the rotatable member 45 similarly as in the case of thesealing member 52.

The rotatable member 45 used in this embodiment is constituted by anarcuate portion 45 b and a rectilinear portion 45 c in cross section asseen in the longitudinal direction of the rotatable member 45, and amounting surface 45 d corresponding to the rectilinear portion 45 c ofthe cross section is provided with a plurality of projections 45 a,arranged in the longitudinal direction, for supporting theabove-described pluralities of the holes 53 a and the holes 44 a.

The sealing member 52 and the toner stirring sheet 44 are, as shown in(a) of FIG. 6, supported at the holes 52 a and the holes 44 a by theprojections 45 a of the rotatable member 45, and thereafter are fixed tothe rotatable member 45 by thermal caulking as shown in (b) of FIG. 6.In this embodiment, the fixing of the sealing member 52 and the tonerstirring sheet 44 is performed by the thermal caulking as describedabove, the fixing is not limited thereto but may also be performed byanother means such as a double-side tape or snap fitting. Further, asregards the mounting surface for the sealing member 52 and the tonerstirring sheet 44, the sealing member 52 and the toner stirring sheet 44may be mounted on the same mounting surface 45 d as in this embodimentor may also be mounted on different surfaces of the rotatable member 45.

(Mounting Method of Rotatable Member Unit 54 and Sealing Member 52)

Next, a mounting method of the rotatable member unit 54 and the sealingmember 52 to the toner accommodating frame 23 will be described usingFIG. 7. In (a) of FIG. 7, an arrow X direction is the longitudinaldirection which is the axial direction of the rotatable member 45, andan arrow Z direction is a widthwise (short) direction perpendicular tothe axial direction.

As shown in (a) of FIG. 7, one end portion 52 b of the sealing member 52fixed to the rotatable member 45 with respect to the widthwise directionis fixed by the thermal welding or the like or a fixing portion 23 b(hatched portion in (a) of FIG. 7) provided at a periphery of a tonersupply opening 23 a of the toner accommodating frame 23. The fixingportion 23 a is constituted by a first fixing portion 23 c extendingalong the longitudinal direction of the toner supply opening 23 a and bysecond and third fixing portions 23 d and 23 e each extending along thewidthwise direction of the toner supply opening 23 a. The second fixingportion 23 d is positioned on a non-driving side opposite with respectto the longitudinal direction, from a side where the driving shaft 14 isprovided in the apparatus main assembly A. The third fixing portion 23 eis positioned on a driving side which is the same side, with respect tothe longitudinal direction, as the side where the driving shaft 14 isprovided in the apparatus main assembly A. Further, the sealing member52 is provided with a folded-back portion U where the sealing member 52is folded back.

As shown in (b) of FIG. 7, the toner supply opening 23 a is sealed(covered) with the sealing member 52 at the fixing portion 23 b.Thereafter, the rotatable member unit 54 is supported by a shaft portion35 a of a stirring gear member 35 through a hole 37 provided in thetoner accommodating frame 23 by inserting a driving-side end portion 45f of the rotatable member 45 into the hole 37. On the other hand, ashaft portion 45 e as a non-driving-side end portion of the rotatablemember 45 is rotatably supported by an unshown hole provided in thetoner accommodating frame 23.

On the driving side, a seal member 36 is provided and constituted so asto prevent toner leakage through the hole 37 of the toner accommodatingframe 23. The rotatable member unit 54 is supported by the toneraccommodating frame 23 and thereafter, the cap member 22 is fixed to thetoner accommodating frame 23 by welding or the like.

(Sandwiching Portion M)

In FIG. 1, (a) and (b) are sectional views of the developing device unit20 in this embodiment, in which (a) is the sectional view of an entiretyof the developing device unit 20 and (b) is an enlarged view showing thefolded-back portion U of the sealing member 52 and a sandwiching portionM in the developing device unit. Cross sections shown in (a) and (b) ofFIG. 1 are planes perpendicular to the toner supply opening 23 a.

In this embodiment, as shown in (a) of FIG. 1, one end portion 52 b ofthe sealing member 52 is welded to the fixing portion 23 c which is aportion on an upper end of the toner supply opening 23 a. Further, atthe sandwiching portion M which is a portion under a lower end of thetoner supply opening 23 a, the sealing member is sandwiched in a statein which the sealing member is folded back with the folded-back portionU as a bottom thereof. The sandwiching portion M is constituted by awall 23 g, provided with the toner supply opening 23 a, constituting thetoner accommodating frame 23 and a part 23 h, opposing the wall 23 g, ofthe toner accommodating frame 23. A portion, of the sealing member 52,sandwiched by the sandwiching portion M is not welded (i.e., nonwelded)in the sandwiching portion M when the sealing member 52 is seen on aplane perpendicular to the toner supply opening 23 a. Further, when thefolded-back portion U of the sealing member 52 is sandwiched by thesandwiching portion M, a depth of the sealing member 52 (the folded-backportion U) is D, a width of the sealing member M is W, and a thicknessof the sealing member 52 is L ((b) of FIG. 1). As a condition of thewidth W at this time, when the width W is narrowed to the extent thatthe sealing member 52 is compressed (deformed), the sealing member 52 isnot disconnected from the sandwiching portion M. For that reason, as acondition that the folded-back sealing member 52 is not compressed,there is a need to satisfy 2L>W. Further, in the case where the width Wis large, it is natural that the sealing member 52 is not in a state inwhich the folded-back portion U is sandwiched in the sandwiching portionM, and therefore as a result of investigation, it was found that W<5L isdesirable. From the above result, as the condition of the width W, it isdesirable that 2L<W<5L is satisfied. In this embodiment, the depth D was10 mm, the width W was 400 μm and the thickness L was 100 μm. Bysandwiching the sealing member 52 in the sandwiching portion M in astate in which the sealing member 52 is folded back in the sandwichingportion M with the folded-back portion U as the bottom thereof, thetoner T is prevented from leaking out of the toner accommodating frame23.

In a conventional constitution, the toner leakage was prevented bybonding the sealing member to the frame by welding, but in this case, aload of a torque when the sealing member is peeled off from the frame islarge. In order to reduce the load, the sealing member is sandwiched, sothat not only the load of the torque is reduced but also a degree of thetoner leakage is reduced. That is, the sandwiching of the sealing member(folded-back portion U) is as if a temporally sealing.

For that reason, in this embodiment, the sealing member and the frameare not welded to each other in a region of the depth D of thesandwiching portion M in (b) of FIG. 1, and in addition, the sealingmember is not welded to also a frame portion DU which is on the depth Dregion and under the opening. That is, a lower portion, of the sealingmember, under the opening (on an upstream side with respect to anunsealing direction) is subjected to the temporary sealing for thesandwiching without being weld.

However, the present invention is not limited thereto, but the frameportion DU under the opening and the sealing member may also be weldedto each other. In this case, compared with conventional welding, atorque load in the above welding is small. That is, the temporarysealing and the welding are used in combination.

(Unsealing Method of Sealing Member 52)

An unsealing operation of the sealing member 52 will be described using(a) to (d) of FIG. 8. When the cartridge B is mounted in the apparatusmain assembly A and the openable door 13 of the apparatus main assemblyA is closed, rotational drive of the apparatus main assembly A isstarted. With the rotational drive of the apparatus main assembly A, thedrum 62 of the cartridge B receives a driving force from the apparatusmain assembly A and is rotated. When the drum 62 is rotationally driven,the rotatable member 45 is started to be rotated in an arrow S directionin (a) of FIG. 8 by a driving gear (not shown) provided in the cartridgeB.

With rotation of the rotatable member 45, the sealing member 52 mountedto the rotatable member unit 54 is subjected to tension and receives aforce in a direction of being spaced from the toner supply opening 23 a,and therefore the folded-back portion U of the sealing member 52 isdisconnected (eliminated) from the sandwiching portion M ((b) of FIG.8). As a result, the sealing member 52 is peeled off from the tonersupply opening 23 a, and therefore the toner T is sent from the toneraccommodating frame 23 in a direction toward a developing sleeve by therotatable member unit 54 ((c) of FIG. 8). Thereafter, with furtherrotation of the rotatable member unit 54, the sealing member 52 ispeeled off from the fixing portion 23 c above the toner supply opening23 a. The toner stirring sheet 44 is mounted at one end portion thereoftogether with the sealing member 52 on the rotatable member 45, andtherefore by the rotation of the rotatable member 45, the toner stirringsheet 44 is rotated simultaneously with the sealing member 52. By thistoner stirring member rotated simultaneously with the sealing member 52,the toner T in the toner chamber 29 is fed while being stirred, and issent toward the toner supplying chamber 28 through the toner supplyopening 23 a. Then, finally, the toner T is coated on the developingsleeve, and the image forming apparatus is in a printable state, so thatthe drive of the apparatus main assembly A stops ((d) of FIG. 8).

(Toner Filling Port and Filling Method)

At the sandwiching portion M, different from the welding, the sealingmember 52 is not completely fixed, and therefore the sealing member 52is required to be prevented from disconnecting from the sandwichingportion M particularly during filling of the toner. For that reason, inthe case where the toner is filled, there is a need that the toner T issent to above the sealing member 52 and using a self-weight of the tonerT, the sealing member 52 is not readily disconnected from the sealingmember M. For that reason, as a filling port C through which the toner Tis filled into the developing device unit 20, the filling port C maydesirably be a hatched region shown in (a) of FIG. 9. Specifically, asthe filling port C, it is desirable that the filling port C is providedin a container wall of the toner accommodating frame 23 on not only aside closer to the toner supply opening 23 a than an axial center of therotatable member unit 54 is but also a side above a rotation locus of arotation shaft of the rotatable member unit 54. However, as shown in 8b) of FIG. 9, in the case where a position where the toner T is filledcan be arbitrarily designated using a nozzle O or the like, the positionof the filling port C is not limited if a filling condition of the tonerT for causing the sealing member 52 to be not readily disconnected fromthe sandwiching portion M is satisfied. Further, also after the fillingof the toner T, movement of the toner T is prevented to the possibleextent by an attitude of the cartridge B, so that it becomes possible toprevent the sealing member 52 from disconnecting from the sandwichingportion M by the movement of the sealing member 52. For that reason,also as regards a toner filling amount, the toner may preferably befilled without providing a space in the toner accommodating frame to thepossible extent.

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example, the case where the sealing member 52 is welded atthe fixing portions 23 c, 23 d, 23 e, 23 f surrounding the toner supplyopening 23 a as shown in (a) of FIG. 10 is used.

In FIG. 10, (b) is a graph in which a rotation start time of the drivingshaft 14 of the apparatus main assembly A is taken as an origin on anabscissa and a magnitude of a torque is represented by an ordinate andin which progression of the torque from the rotational drive of thedriving shaft 14. In the graph of (b) of FIG. 10, a solid linerepresents Comparison Example and shows the torque during unsealing inthe case where the sealing member 52 is welded to an entirety of aperiphery of the toner supply opening 23 a. Further, in the graph of (b)of FIG. 10, a broken line represents Embodiment 1 and shows the torqueduring unsealing in the constitution in which the sealing member 52 issandwiched in the sandwiching portion M.

Two peaks t1 and t2 where the torque in Comparison Example in (b) ofFIG. 10 increases will be described. The peak t1 is a torque peak in thecase where the welding at the fixing portion 23 f is eliminated, and thepeak t2 is a torque peak in the case where the welding at the fixingportion 23 c is eliminated. When these torque peaks are compared witheach other, it is understood that in the same constitution, a maximumtorque at t1 is larger than a maximum torque at t2. This is becausethese torques are those immediately after the start of the drive of thedriving shaft 14 and therefore the toner T in the toner accommodatingframe is not loosened and thus the torque of the rotatable member unit54 rotating in the toner T is large. On the other hand, at the peak t2,the toner T is loosened by the rotatable member and therefore comparedwith the peak t1, the sealing member 52 can be peeled off from thefixing portion 23 c with a small torque. Similarly, an increased torquepeak t1′ in Embodiment 2 (this embodiment) in (b) of FIG. 10 shows atorque in the case where the sealing member 52 sandwiched in thesandwiching portion M is disconnected from the sandwiching portion M,and it is understood that compared with t1 in Comparison Example inwhich the sealing member is welded, the torque becomes small. Further,as regards the peak t2, the sealing member is welded in both ofComparison Example and Embodiment 1, and therefore it is understood thatthe torque is the same.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value and thus to suppress anecessary torque as a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, the cartridge B in the case where thesealing member 52 is welded to the entirety of the periphery of thetoner supply opening 23 a ((a) of FIG. 10) is used similarly as in thecase of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 1 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem.

From the comparison and investigation described above, in theconstitution in this embodiment, it becomes possible to suppress thetorque during unsealing of the sealing member 52 while preventing thetoner leakage from the cartridge B.

[Embodiment 2]

Embodiment 2 is characterized in that in addition to the constitution inEmbodiment 1 in which the folded-back portion of the sealing member 52is sandwiched, sealing is made using a restoring force of thefolded-back portion so that the toner leakage can be further prevented.

In Embodiment 2, an apparatus main assembly A and an image formingprocess are the same as those in Embodiment 1, and therefore descriptionof a sandwiching portion M of a developing device unit 20 will be made.

(Sandwiching Portion M)

In FIG. 11, (a) and (b) are sectional views of the developing deviceunit 20 in this embodiment, in which (a) is the sectional view of anentirety of the developing device unit 20 and (b) is an enlarged viewshowing the folded-back portion U of the sealing member 52 and asandwiching portion M in the developing device unit. Cross sectionsshown in (a) and (b) of FIG. 11 are planes perpendicular to the tonersupply opening 23 a.

In this embodiment, as shown in (a) of FIG. 11, one end portion 52 b ofthe sealing member 52 is welded to the fixing portion 23 c which is aportion on an upper end of the toner supply opening 23 a and welded tothe side fixing portions 23 d, 23 e ((a) of FIG. 10). Further, at thesandwiching portion M which is a portion under a lower end of the tonersupply opening 23 a, the sealing member is sandwiched the toneraccommodating frame 23 in a state in which the sealing member is foldedback with the folded-back portion U as an inflection point thereof. Thesandwiching portion M is constituted by a wall 23 g, provided with thetoner supply opening 23 a, constituting the toner accommodating frame 23and a part 23 h, opposing the wall 23 g, of the toner accommodatingframe 23. However, depending on a magnitude of the toner supply opening23 a, the sealing member 52 is not particularly required to be welded atthe fixing portions 23 d, 23 e. Further, a portion, of the sealingmember 52, sandwiched by the sandwiching portion M is not welded (i.e.,nonwelded) in the sandwiching portion M when the sealing member 52 isseen on a plane perpendicular to the toner supply opening 23 a.

In this embodiment, different from Embodiment 1, the sealing member 52is not in the state in which the sealing member 52 is (sharply) foldedback with the folded-back portion U as the bottom thereof, but is(loosely) folded back so as to have the inflection point at thefolded-back portion U. For that reason, the sealing member 52 issandwiched in the sandwiching portion M of the toner accommodating frame23 by using a restoring force F of the sealing member 52. Herein, therestoring force F refers to a force F (indicated by arrows in (a) ofFIG. 12) by which the sealing member 52 is restored to an original statein the case where the sealing member 52 is flexed (bent) using aflexible material as shown in (a) of FIG. 12. In this case, a conditionin which the restoring force F of the sealing member 52 is obtained andthus the toner T can be sealed in the toner accommodating frame 23 willbe described using (b) of FIG. 12.

A depth D in which the sealing member 52 is sandwiched in thesandwiching portion M may only be required to be not less than a radiusR of an arcuate portion, i.e., D>R. This is because, in the case of D≦R,the folded-back portion of the sealing member 52 is shallowly sandwichedin the sandwiching portion M and is likely to be restored to theoriginal state by the restoring force F and therefore is liable todisconnect from the sandwiching portion M when is shallowly sandwiched.

Further, as regards a width W of the sandwiching portion M, 2R>W mayonly be required in order to obtain the restoring force F in the casewhere the sealing member 52 is folded back. This is also a conditionsuch that similarly as in the case of the sandwiching depth D, thesealing member 52 is shallowly sandwiched in the sandwiching portion Mand is prevented from easily disconnecting from the sandwiching portionM.

Further, a material of the sealing member 52 may only be required to beflexible, and a thickness thereof is needed to be not less than athickness in which the restoring force generates and not more than athickness in which the sealing member 52 can be folded back. Values ofthese thicknesses are determined depending on the material of thesealing member 52.

From the above, in this embodiment, the depth D of the sandwichingportion M is 10 mm, and the width W of the sandwiching portion M is 5mm. Further, the thickness L of the sealing member 52 is 100 μm. Thematerial of the sealing member 52 is a flexible material, such as PET,PC or PPS, having an adhesive layer which is melted by heat and thus canbe welded to a frame (container). By sandwiching the sealing member 52in the sandwiching portion M in a folded-back state, the toner T isprevented from leaking out of the toner accommodating frame 23.

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example, the case where the sealing member 52 is welded atthe fixing portions 23 c, 23 d, 23 e, 23 f surrounding the toner supplyopening 23 a as shown in (a) of FIG. 10 is used.

FIG. 13 is a graph in which a rotation start time of the driving shaft14 of the image forming apparatus main assembly A is taken as an originon an abscissa and a magnitude of a torque is represented by an ordinateand in which progression of the torque from the rotational drive of thedriving shaft 14. In the graph of (b) of FIG. 13, a solid linerepresents Comparison Example and shows the torque during unsealing inthe case where the sealing member 52 is welded to an entirety of aperiphery of the toner supply opening 23 a as shown in (a) of FIG. 10.Further, in the graph of FIG. 13, a broken line represents Embodiment 2and shows the torque during unsealing in the constitution in which thesealing member 52 is sandwiched in the sandwiching portion M.

Of two peaks t1 and t2 where the torque in Comparison Example in FIG. 13increases, as described in Embodiment 1, the peak t1 is a torque peak inthe case where the welding at the fixing portion 23 f is eliminated, andthe peak t2 is a torque peak in the case where the welding at the fixingportion 23 c is eliminated. Similarly, an increased torque peak t1″ inEmbodiment 2 (this embodiment) in FIG. 13 shows a torque in the casewhere the sealing member 52 sandwiched in the sandwiching portion M isdisconnected from the sandwiching portion M, and it is understood thatcompared with t1 in Comparison Example in which the sealing member iswelded, the torque becomes small. However, the sealing member 52 issandwiched using the restoring force F and therefore the torque islarger than the torque in Embodiment 1. Further, as regards the peak t2,the sealing member is welded in both of Comparison Example andEmbodiment 1, and therefore it is understood that the torque is thesame.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value and thus to suppress anecessary torque as a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, the cartridge B in the case where thesealing member 52 is welded to the entirety of the periphery of thetoner supply opening 23 a ((a) of FIG. 10) is used similarly as in thecase of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 2 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem.Further, compared with Embodiment 1, the sealing is made using therestoring force F in this embodiment, and therefore the sealing can bemade more effectively against the toner leakage.

From the comparison and investigation described above, in theconstitution in this embodiment, it becomes possible to suppress thetorque during unsealing of the sealing member 52 while furtherpreventing the toner leakage from the cartridge B.

[Embodiment 3]

Embodiment 3 is characterized in that in addition to the constitution inEmbodiment 2 in which the sealing is made using the restoring force F ofthe sealing member 52, also at a portion above the opening 23 a, thefolded-back portion is similarly sandwiched and the sealing is madeusing the restoring force F of the sealing member 52.

In Embodiment 3, an apparatus main assembly A and an image formingprocess are the same as those in Embodiment 1, and therefore descriptionof a sandwiching portion M of a developing device unit 20 will be made.

(Sandwiching Portion M)

In FIG. 14, (a) to (c) are sectional views of the developing device unit20 in this embodiment, in which (a) is the sectional view of an entiretyof the developing device unit 20, and (b) and (c) are enlarged viewsshowing folded-back portions U, V of the sealing member 52 andsandwiching portions M, N in the developing device unit. Cross sectionsshown in (a) to (c) of FIG. 14 are planes perpendicular to the tonersupply opening 23 a.

In this embodiment, as shown in (a) and (b) of FIG. 14, one end portion52 b of the sealing member 52 is sandwiched in the sandwiching portion Nwhich is a portion on an upper end of the toner supply opening 23 a in astate in which the sealing member 52 is folded back with the folded-backportion V as an inflection point thereof. For this reason, using therestoring force F, the sandwiching portion N sandwiches the sealingmember 52. Further, at the sandwiching portion M which is a portionunder a lower end of the toner supply opening 23 a, the sealing memberis sandwiched in a state in which the sealing member is folded back withthe folded-back portion U as an inflection point thereof. For thatreason, similarly as in Embodiment 2, the sealing member 52 issandwiched in the sandwiching portion M by using the restoring force F.Further, although the side fixing portions 23 d, 23 e are not shown inFIG. 14, at the periphery of the toner supply opening 23 a, the sealingmember 52 is welded to the side fixing portions 23 d, 23 e sandwichingthe toner supply opening 23 a in this embodiment. However, depending ona magnitude of the toner supply opening 23 a, a constitution in whichthe fixing portions 23 d, 23 e are not provided, i.e., a constitution inwhich the sealing member 52 is not welded may also be employed. Further,a portion, of the sealing member 52, sandwiched by the sandwichingportion M is not welded (i.e., nonwelded) in each of the sandwichingportions M, N when the sealing member 52 is seen on a planeperpendicular to the toner supply opening 23 a. Each of the sandwichingportions M, N is, similarly as in the above-described embodiments,constituted by the wall 23 g, provided with the toner supply opening 23a, constituting the toner accommodating frame 23 and the part 23 h,opposing the wall 23 g, of the toner accommodating frame 23.

As a condition in which the restoring force F of the sealing member 52is obtained and thus the toner can be sealed in the toner accommodatingframe 23, similarly as in Embodiment 2, as shown in (b) of FIG. 12, adepth D in which the sealing member 52 is sandwiched in the sandwichingportion M may only be required to be not less than a radius R of anarcuate portion, i.e., D>R. This is because, in the case of D≦R, thefolded-back portion of the sealing member 52 is shallowly sandwiched inthe sandwiching portion M and is likely to be restored to the originalstate by the restoring force F and therefore is liable to disconnectfrom the sandwiching portion M when is shallowly sandwiched.

Further, as regards a width W of the sandwiching portion M, 2R>W mayonly be required in order to obtain the restoring force F in the casewhere the sealing member 52 is folded back. This is also a conditionsuch that similarly as in the case of the sandwiching depth D, thesealing member 52 is shallowly sandwiched in the sandwiching portion Mand is prevented from easily disconnecting from the sandwiching portionM.

Further, a material of the sealing member 52 may only be required to beflexible, and a thickness thereof is needed to be not less than athickness in which the restoring force generates and not more than athickness in which the sealing member 52 can be folded back. Values ofthese thicknesses are determined depending on the material of thesealing member 52.

Similarly, also at the sandwiching portion N, only the direction ischanged from the downward direction to the upward direction, andtherefore when a condition similar to the condition in the case of thesandwiching portion M is satisfied, the toner T can be sealed in thetoner accommodating frame 23 by using the restoring force F.

From the above, in this embodiment, the depth D of each of thesandwiching portions M, N is 10 mm, and the width W of each of thesandwiching portions M, N is 5 mm. Further, the thickness L of thesealing member 52 is 100 μm. The material of the sealing member 52 is aflexible material, such as PET, PC or PPS, having an adhesive layerwhich is melted by heat and thus can be welded to the container. Bysandwiching the sealing member 52 in each of the sandwiching portions M,N in a folded-back state, the toner T is prevented from leaking out ofthe toner accommodating frame 23.

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example, the case where the sealing member 52 is welded atthe fixing portions 23 c, 23 d, 23 e, 23 f surrounding the toner supplyopening 23 a as shown in (a) of FIG. 10 is used.

FIG. 15 is a graph in which a rotation start time of the driving shaft14 of the apparatus main assembly A is taken as an origin on an abscissaand a magnitude of a torque is represented by an ordinate and in whichprogression of the torque from the rotational drive of the driving shaft14. In the graph of (b) of FIG. 15, a solid line represents ComparisonExample and shows the torque during unsealing in the case where thesealing member 52 is welded to an entirety of a periphery of the tonersupply opening 23 a as shown in (a) of FIG. 10. Further, in the graph ofFIG. 15, a broken line represents Embodiment 3 and shows the torqueduring unsealing in the constitution in which the sealing member 52 issandwiched in each of the sandwiching portions M, N.

Of two peaks t1 and t2 where the torque in Comparison Example in FIG. 15increases, as described in Embodiment 1, the peak t1 is a torque peak inthe case where the welding at the fixing portion 23 f is eliminated, andthe peak t2 is a torque peak in the case where the welding at the fixingportion 23 c is eliminated. Similarly, an increased torque peak t3 inEmbodiment 3 (this embodiment) in FIG. 15 shows a torque in the casewhere the sealing member 52 sandwiched in the sandwiching portion M isdisconnected from the sandwiching portion M, and it is understood thatcompared with t1 in Comparison Example in which the sealing member iswelded, the torque becomes small. Further, an increased torque peak T4in Embodiment 3 (this embodiment) in FIG. 15 shows a torque in the casewhere the sealing member 52 sandwiched in the sandwiching portion N isdisconnected from the sandwiching portion N, and it is understood thatcompared with t2 in Comparison Example in which the sealing member iswelded, the torque becomes small.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value and thus to suppress anecessary torque as a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, the cartridge B in the case where thesealing member 52 is welded to the entirety of the periphery of thetoner supply opening 23 a ((a) of FIG. 10) is used similarly as in thecase of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 3 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem inuse.

From the comparison and investigation described above, according to thisembodiment, it becomes possible to suppress the torque during unsealingof the sealing member 52 while further preventing the toner leakage fromthe cartridge B.

Further, as shown in FIG. 16, even when a constitution opposite to theconstitution shown in FIG. 14 in that a direction of folding back of thesealing member 52 in the sandwiching portion N at the portion above thetoner supply opening 23 a is employed, the torque change device is thesame as that in this embodiment, so that an effect similar to the effectof the present invention can be obtained. In this case, at the peripheryof the toner supply opening 23 a, the fixing portion 23 b is notprovided, so that there was no problem also in terms of the tonerleakage and therefore an effects similar to the effect of the presentinvention was obtained.

[Embodiment 4]

Embodiment 4 is characterized in that in addition to the constitution inEmbodiment 2 in which the folded-back portion of the sealing member 52is sandwiched at the portion under the opening, a sandwiching opening M′is made narrower than that in Embodiment 2, so that the sealing member52 does not readily disconnect from the sandwiching portion M and thusthe toner does not readily leak out further by narrowing a sandwichingport M′ compared with that in Embodiment 2.

In Embodiment 4, an apparatus main assembly A and an image formingprocess are the same as those in Embodiment 1, and therefore descriptionof a sandwiching portion M of a developing device unit 20 will be made.

(Sandwiching Portion M)

In FIG. 17, (a) and (b) are sectional views of the developing deviceunit 20 in this embodiment, in which (a) is the sectional view of anentirety of the developing device unit 20 and (b) is an enlarged viewshowing the folded-back portion U of the sealing member 52 and asandwiching portion M and the sandwiching port M′ in the developingdevice unit. Cross sections shown in (a) and (b) of FIG. 17 are planesperpendicular to the toner supply opening 23 a.

In this embodiment, as shown in (a) of FIG. 17, one end portion 52 b ofthe sealing member 52 is welded to the fixing portion 23 c which is aportion on an upper end of the toner supply opening 23 a and welded tothe side fixing portions 23 d, 23 e ((a) of FIG. 10). Further, at thesandwiching portion M which is a portion under a lower end of the tonersupply opening 23 a, the sealing member is sandwiched the toneraccommodating frame 23 in a state in which the sealing member is foldedback with the folded-back portion U as an inflection point thereof.However, depending on a magnitude of the toner supply opening 23 a, thefixing portions 23 d, 23 e are not needed. Further, in Embodiment 4, inaddition to the sandwiching of the sealing member 52 in the sandwichingportion M by using the restoring force F as in Embodiment 2, thesandwiching port M′ which is an entering port for the sealing member 52at the sandwiching portion M. Further, a portion, of the sealing member52, sandwiched at the sandwiching portion M and the sandwiching port M′is not welded in the sandwiching portion as seen in a planeperpendicular to the toner supply opening 23 a. The sandwiching portionM is constituted by a wall 23 g, provided with the toner supply opening23 a, constituting the toner accommodating frame 23 and a part 23 h,opposing the wall 23 g, of the toner accommodating frame 23.

For that reason, as a condition at the sandwiching portion M, when awidth of the sandwiching portion M is W and a width of the sandwichingport M′ is W′, W′>W is satisfied. Further, when the width W′ becomesexcessively narrow, then the sealing member 52 does not readilydisconnect from the sandwiching portion M, and therefore the width W′ isrequired to be not less than twice the thickness L of the sealing member52. For that reason, as a condition of the width W′ of the sandwichingport M′, 2L<W′<W is satisfied. Further, when a distance from a lower endportion of the sandwiching port M′ to the folded-back portion U of thesealing member 52 is a sandwiching depth D′ of the sealing member 52 inthe sandwiching portion M, the sandwiching depth D′ may only be requiredto be not less than a radius R of an arcuate portion, i.e., D′>R. Thisis because, similarly as in Embodiment 2, in the case of D′≦R, thefolded-back portion of the sealing member 52 is shallowly sandwiched inthe sandwiching portion M and is likely to be restored to the originalstate by the restoring force F and therefore is liable to disconnectfrom the sandwiching portion M when is shallowly sandwiched.

From the above, in this embodiment, the depth D of the sandwichingportion M is 10 mm, and the width W of the sandwiching portion M is 5mm. Further, the width W′ of the sandwiching port M′ is 2 mm. Further,the thickness L of the sealing member 52 is 100 μm. The material of thesealing member 52 is a flexible material, such as PET, PC or PPS, havingan adhesive layer which is melted by heat and thus can be welded to thecontainer. By sandwiching the sealing member 52 in the sandwichingportion M and the sandwiching port M′ in a folded-back state, the tonerT is prevented from leaking out of the toner accommodating frame 23.

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example 1, a torque in the case where the sealing member 52is welded at the fixing portions 23 c, 23 d, 23 e, 23 f surrounding thetoner supply opening 23 a as shown in (a) of FIG. 10 is shown. AsComparison Example 2, a torque in the case where the sealing member 52is sandwiched by the restoring force F at the sandwiching portion M inEmbodiment 2 (FIG. 11) is shown.

FIG. 18 is a graph in which a rotation start time of the driving shaft14 of the apparatus main assembly A is taken as an origin on an abscissaand a magnitude of a torque is represented by an ordinate and in whichprogression of the torque from the rotational drive of the driving shaft14. In the graph of (b) of FIG. 18, a solid line represents ComparisonExample and shows the torque during unsealing in the case where thesealing member 52 is welded to an entirety of a periphery of the tonersupply opening 23 a as shown in (a) of FIG. 10. Further, in the graph ofFIG. 18, a broken line represents Comparison Example 2 and shows thetorque in the case where the sealing member 52 is sandwiched by therestoring force F at the sandwiching portion M in Embodiment 2. In thegraph of FIG. 18, a chain line represents a constitution of Embodiment 4(this embodiment) and shows the torque during unsealing in the casewhere the sandwiching port M′ is made narrower than the sandwichingportion M.

In FIG. 18, an increased torque peak t5 in this embodiment is the torquein the case where the sealing member 52 sandwiched in the sandwichingportion M disconnects from the sandwiching portion M, and an increasedtorque peak t6 shows the torque in the case where the sealing member 52welded to the sandwiching portion 23 c is peeled off from the fixingportion 23 c. A torque peak t1 in Comparison Example 1 shows the torquein the case where the sealing member 52 is peeled off from the fixingportion 23 f, and a torque peak t2 shows the torque in the case wherethe sealing member 52 is peeled off from the fixing portion 23 c.Further, a torque peak t1′ in Comparison Example 2 is the torque in thecase where the sealing member 52 is peeled off from the sandwichingportion M, and a torque peak t2′ shows the torque in the case where thesealing member 52 is peeled off from the sandwiching portion 23 c.Particularly, when the torque peaks t1, t1′ and t5 are compared, it isunderstood that t5 is larger than t1′ and is smaller than t1. Further,the torque peaks t2, t2′ and t6 have the same constitution, andtherefore it is understood that the torques are the same.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value compared with the case of thewelding in Comparison Example 1 and thus to suppress a necessary torqueas a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, as Comparison Example, the cartridge B inthe case where the sealing member 52 is welded to the entirety of theperiphery of the toner supply opening 23 a ((a) of FIG. 10) is usedsimilarly as in the case of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 4 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem inuse.

From the comparison and investigation described above, in theconstitution in this embodiment, it becomes possible to suppress thetorque during unsealing of the sealing member 52 while furtherpreventing the toner leakage from the cartridge B.

[Embodiment 5]

Embodiment 5 is characterized in that in addition to the constitution inEmbodiment 4 in which the sealing member 52 does not readily disconnectfrom the sandwiching portion M by narrowing the sandwiching port M′, theperiphery of the sandwiching port M′ is formed with a sponge member andthe sealing member 52 is sandwiched in a folded-back state. As a result,the torque during unsealing is suppressed while the sealing member 52does not readily disconnect through the sandwiching port M′.

In Embodiment 5, an image forming apparatus main assembly A and an imageforming process are the same as those in Embodiment 1, and thereforedescription of a sandwiching portion M of a developing device unit 20will be made.

(Sandwiching Portion M)

In FIG. 19, (a) and (b) are sectional views of the developing deviceunit 20 in this embodiment, in which (a) is the sectional view of anentirety of the developing device unit 20 and (b) is an enlarged viewshowing the folded-back portion U of the sealing member 52, asandwiching portion M and the sandwiching port M′ in the developingdevice unit. Cross sections shown in (a) and (b) of FIG. 19 are planesperpendicular to the toner supply opening 23 a.

In this embodiment, as shown in (a) of FIG. 19, one end portion 52 b ofthe sealing member 52 is welded to the fixing portion 23 c which is aportion on an upper end of the toner supply opening 23 a and welded tothe side fixing portions 23 d, 23 e ((a) of FIG. 10). However, dependingon a magnitude of the toner supply opening 23 a, the sealing member 52is not required to be welded at the fixing portions 23 d, 23 e. Further,at the sandwiching portion M which is a portion under a lower end of thetoner supply opening 23 a, the sealing member is sandwiched the toneraccommodating frame 23 in a state in which the sealing member is foldedback with the folded-back portion U as an inflection point thereof. Aportion, of the sealing member 52, sandwiched at the sandwiching portionM is not welded in the sandwiching portion M as seen in a planeperpendicular to the toner supply opening 23 a. In Embodiment 5, as inEmbodiment 4, the constitution in which the sandwiching port M′ isnarrowed and the periphery of the sandwiching port M′ is formed with asponge member Q (hatched portion of FIG. 19) to sandwich the sealingmember 52 is employed. The sandwiching portion M is constituted by awall 23 g, provided with the toner supply opening 23 a, constituting thetoner accommodating frame 23 and a part 23 h, opposing the wall 23 g, ofthe toner accommodating frame 23. At the sandwiching port M′, the wall23 g and the sponge member Q oppose each other. For that reason, as acondition of the sandwiching port M′, when a width of the sandwichingportion M is W and a width of the sandwiching port M′ is W′, W′>W issatisfied. In Embodiment 4, the lower limit of the width W′ was twicethe thickness L of the sealing member 52, but in this embodiment, theperiphery of the sandwiching port M′ is formed using the sponge memberQ, and therefore the lower limit of the width W′ can be made furthersmall. However, the width W of the sandwiching portion M is required tobe larger than twice the thickness L of the sealing member 52, andtherefore there is a need to satisfy 2L<W.

From the above, in this embodiment, as a condition of the sandwichingport M′, W′<W and 2L<W are satisfied. Specifically, W=10 mm, W′=5 mm andL=100 μm are set. The material of the sealing member 52 is a flexiblematerial, such as PET, PC or PPS, having an adhesive layer which ismelted by heat and thus can be welded to a frame (container).

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example 1, a torque in the case where the sealing member 52is welded at the fixing portions 23 c, 23 d, 23 e, 23 f surrounding thetoner supply opening 23 a as shown in (a) of FIG. 10 is shown. AsComparison Example 2, a torque in the case where the sealing member 52is sandwiched by the restoring force F at the sandwiching portion M inEmbodiment 2 (FIG. 11) is shown.

FIG. 20 is a graph in which a rotation start time of the driving shaft14 of the apparatus main assembly A is taken as an origin on an abscissaand a magnitude of a torque is represented by an ordinate and in whichprogression of the torque from the rotational drive of the driving shaft14. In the graph of (b) of FIG. 20, a solid line represents ComparisonExample and shows the torque during unsealing in the case where thesealing member 52 is welded to an entirety of a periphery of the tonersupply opening 23 a as shown in (a) of FIG. 10. Further, in the graph ofFIG. 20, a broken line represents Comparison Example 2 and shows thetorque in the case where the sealing member 52 is sandwiched by therestoring force F at the sandwiching portion M in Embodiment 2. In thegraph of FIG. 20, a chain line represents a constitution of Embodiment 4(this embodiment) and shows the torque during unsealing in the casewhere the sandwiching port M′ is made narrower than the sandwichingportion M and the sponge member Q is used.

In FIG. 20, an increased torque peak t7 in this embodiment is the torquein the case where the sealing member 52 sandwiched in the sandwichingportion M disconnects from the sandwiching portion M, and an increasedtorque peak t8 shows the torque in the case where the sealing member 52is peeled off from the fixing portion 23 c. A torque peak t1 inComparison Example 1 shows the torque in the case where the sealingmember 52 is peeled off from the fixing portion 23 f, and a torque peakt2 shows the torque in the case where the sealing member 52 is peeledoff from the fixing portion 23 c. Further, a torque peak t1′ inComparison Example 2 is the torque in the case where the sealing member52 is peeled off from the sandwiching portion M, and a torque peak t2′is the torque in the case where the sealing member 52 is peeled off fromthe sandwiching portion 23 c. Particularly, when the torque peaks t1,t1′ and t7 are compared, in this embodiment, the sealing member 52 issandwiched more tightly than in Comparison Example 2 and therefore, itis understood that the torque peak t7 in this embodiment is larger thanthe torque peak t1′ in Comparison Example 2. However, it is understoodthat compared with the torque peak t1 in Embodiment 1, the torque peakt7 is not the torque peak in the case of the welding and thus is lowerthan the torque peak t1 as a peak value. Further, the torque peaks t2,t2′ and t8 have the same constitution, and therefore it is understoodthat the torque peaks are the same.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value compared with the case of thewelding in Comparison Example 1 and thus to suppress a necessary torqueas a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame 23 was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, as Comparison Example, the cartridge B inthe case where the sealing member 52 is welded to the entirety of theperiphery of the toner supply opening 23 a ((a) of FIG. 10) is usedsimilarly as in the case of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 5 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem inuse.

From the comparison and investigation described above, in theconstitution in this embodiment, it becomes possible to suppress thetorque during unsealing of the sealing member 52 while furtherpreventing the toner leakage from the cartridge B.

[Embodiment 6]

Embodiment 6 is characterized in that different from Embodiment 5 inwhich the periphery of the sandwiching port M′ is formed with the spongemember Q, the sponge member Q is mounted to define the opening tosandwich the sealing member 52.

In Embodiment 6, an apparatus main assembly A and an image formingprocess are the same as those in Embodiment 1, and therefore descriptionof a sandwiching portion M of a developing device unit 20 will be made.

(Sandwiching Portion M)

In FIG. 21, (a) and (b) are sectional views of the developing deviceunit 20 in this embodiment, in which (a) is the sectional view of anentirety of the developing device unit 20 and (b) is an enlarged viewshowing the folded-back portion U of the sealing member 52 and asandwiching portion M in the developing device unit. Cross sectionsshown in (a) and (b) of FIG. 21 are planes perpendicular to the tonersupply opening 23 a.

In this embodiment, as shown in (a) of FIG. 21, one end portion 52 b ofthe sealing member 52 is welded to the fixing portion 23 c which is aportion on an upper end of the toner supply opening 23 a and welded tothe side fixing portions 23 d, 23 e ((a) of FIG. 10). Further, at thesandwiching portion M which is a portion under a lower end of the tonersupply opening 23 a, the sealing member is sandwiched in a state inwhich the sealing member is folded back at the folded-back portion U.However, depending on a magnitude of the toner supply opening 23 a, thesealing member 52 is not particularly required to be welded at thefixing portions 23 d, 23 e. Further, a portion, of the sealing member52, sandwiched by the sandwiching portion M is not welded (i.e.,nonwelded) in the sandwiching portion M when the sealing member 52 isseen on a plane perpendicular to the toner supply opening 23 a.

Further, in this embodiment, an assisting member 53 is provided at aportion blow the toner supply opening 23 a and then the sponge member Qis mounted on the assisting member 53. The sponge member Q is assistedby the assisting member 53 from a side opposite from a contact portionwith the sealing member 52. The sandwiching portion M is constituted bythe wall 23 g, provided with the toner supply opening 23 a, constitutingthe toner accommodating frame 23 and by the sponge member Q providedopposed to the wall 23 g. Then, the folded-back portion of the sealingmember 52 is sandwiched by the wall 23 g and the sponge member Q, sothat the sealing member 52 does not readily disconnect from thesandwiching portion M and thus the toner leakage is prevented. Further,in this embodiment, the assisting member 53 is provided using a SUSplate as shown in FIG. 21 and is fixed with a double-side tape at theportion below the toner supply opening 23 a. When the width of thesandwiching portion M is W and the thickness of the sealing member 52 isL, in this embodiment, as a condition in which the sealing member 52 issandwiched by the width 23 g and the sponge member Q, 2L>W is satisfied.Specifically, in this embodiment, the width W of the sandwiching portionM and the thickness L of the sealing member 52 are 180 μm and 100 μm,respectively. The material of the sealing member 52 is a flexiblematerial, such as PET, PC or PPS, having an adhesive layer which ismelted by heat and thus can be welded to a frame (container).

(Verification Experiment)

How a torque (N.m) of the driving shaft 14 during unsealing of thesealing member 52 in this embodiment changes will be verified. AsComparison Example 1, a torque in the case where the sealing member 52is welded at the fixing portions 23 c, 23 d, 23 e, 23 f surrounding thetoner supply opening 23 a as shown in (a) of FIG. 10 is shown. AsComparison Example 2, a torque in the case where the sealing member 52is sandwiched by the restoring force F at the sandwiching portion M inEmbodiment 2 (FIG. 11) is shown.

FIG. 22 is a graph in which a rotation start time of the driving shaft14 of the apparatus main assembly A is taken as an origin on an abscissaand a magnitude of a torque is represented by an ordinate and in whichprogression of the torque from the rotational drive of the driving shaft14. In the graph of (b) of FIG. 22, a solid line represents ComparisonExample and shows the torque during unsealing in the case where thesealing member 52 is welded to an entirety of a periphery of the tonersupply opening 23 a as shown in (a) of FIG. 10. Further, in the graph ofFIG. 22, a broken line represents Comparison Example 2 and shows thetorque in the case where the sealing member 52 is sandwiched by therestoring force F at the sandwiching portion M in Embodiment 2. In thegraph of FIG. 22, a chain line represents a constitution of Embodiment 4(this embodiment) and shows the torque during unsealing in the casewhere the sandwiching sealing member 52 is sandwiched using the spongemember Q mounted on the assisting member 53.

In FIG. 22, a torque peak t9 in this embodiment is the torque in thecase where the sealing member 52 sandwiched using the sponge member Qdisconnects from the sandwiching portion M, and a torque peak t10 is thetorque in the case where the sealing member 52 is peeled off from thefixing portion 23 c. A torque peak t1 in Comparison Example 1 is thetorque in the case where the sealing member 52 is peeled off from thefixing portion 23 f, and a torque peak t2 is the torque in the casewhere the sealing member 52 is peeled off from the fixing portion 23 c.Further, a torque peak t1′ in Comparison Example 2 is the torque in thecase where the sealing member 52 is peeled off from the sandwichingportion M, and a torque peak t2′ is the torque in the case where thesealing member 52 is peeled off from the sandwiching portion 23 c. Whenthe torque peaks t1, t1′ and t9 are compared, it is understood that thetorque peak t9 is larger than the torque peak t1 in the case of thewelding. Further, in this embodiment, the sealing member 52 issandwiched more tightly than in Comparison Example 2 and therefore it isunderstood that the torque peak t9 is larger than the torque peak t1′ inComparison Example 2. Further, the torque peaks t2, t2′ and t10 have thesame constitution, and therefore it is understood that the torques arethe same.

From the above, in the constitution in this embodiment, it becomespossible to suppress a torque peak value compared with the case of thewelding in Comparison Example 1 and thus to suppress a necessary torqueas a whole.

Further, comparison and investigation regarding toner leakage from thetoner accommodating frame 23 was conducted. As the comparison andinvestigation regarding the toner leakage, a drop test of the cartridgeB was conducted. The drop test is conducted in a packaged state in whichthe cartridge B is placed in an unused case. Assuming that the cartridgeB is transported, the cartridge B is dropped from a height of 100 cmwhile being in the packaged state, and then whether or not the tonerleaks out of the cartridge B is checked. As an object to be comparedwith that in this embodiment, as Comparison Example, the cartridge B inthe case where the sealing member 52 is welded to the entirety of theperiphery of the toner supply opening 23 a ((a) of FIG. 10) is usedsimilarly as in the case of the measurement of the torque.

In the above-described comparison and investigation, in both of theconstitutions in Embodiment 6 and Comparison Example, the toner leakagedid not generate, and therefore it was confirmed that the toner T wasable to be sealed in the toner accommodating frame 23 with no problem inuse.

From the comparison and investigation described above, in theconstitution in this embodiment, it becomes possible to suppress thetorque during unsealing of the sealing member 52 while furtherpreventing the toner leakage from the cartridge B.

[Other Embodiments]

In the above-described embodiments, the process cartridge including thedeveloping device unit was described as an example, but the presentinvention is not limited thereto. Separately from the process cartridgeincluding the photosensitive drum, a developing device detachablymountable to the image forming apparatus main assembly may also beindependently provided. Alternatively, a developer container such as atoner bottle including the toner accommodating frame provided with theopening and the sealing member for sealing the opening may also be used.

In the above-described embodiments, as the process cartridge detachablymountable to the image forming apparatus main assembly, a processcartridge prepared by integrally assembling the photosensitive drum and,as the process means actable on the photosensitive drum, the chargingmeans, the developing means and the cleaning means into a unit wasdescribed as an example. However, the present invention is not limitedthereto. The process cartridge may also be a process cartridgeintegrally including in addition to the photosensitive drum and thedeveloping means, either one of the charging means and the cleaningmeans as a unit.

Further, in the above-described embodiments, as the image formingapparatus, the printer was described as an example, but the presentinvention is not limited thereto. For example, other image formingapparatuses such as a copying machine, a facsimile machine and amulti-function machine having a combination of functions as thesemachines may also be used. By applying the present invention to theseimage forming apparatuses, a similar effect can be obtained.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2015-105995 filed on May 26, 2015, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A developer container comprising: a frame,provided with an opening, for accommodating developer; a sealing memberfor sealing the opening; a rotatable member rotatable to wind up saidsealing member; and a sandwiching portion for sandwiching a part of saidsealing member, wherein in a state in which said part of said sealingmember is folded back in said sandwiching portion and before saidrotatable member starts to rotate, said part of said sealing member isnonwelded in said sandwiching portion.
 2. A developer containeraccording to claim 1, wherein said frame includes a stirring member,mounted on said rotatable member, for feeding the developer toward theopening while stirring the developer, and wherein said sealing member ismounted on said rotatable member at one end portion thereof, and saidsealing member and said stirring member are simultaneously rotatable byrotation of said rotatable member.
 3. A developer container according toclaim 1, wherein when a depth of said sandwiching portion before saidfolded back portion is sandwiched is D, a width of said sandwichingportion is W and a thickness of said sealing member is L, a condition ofthe width W of said sandwiching portion is 2L<W<5L.
 4. A developercontainer according to claim 1, wherein, when a depth of saidsandwiching portion before said folded back portion is sandwiched is D,a driving of said sandwiching portion before said folded back portion issandwiched is L, a width of said sandwiching portion is W and a radiusof an arcuate portion of said folded back portion is R, D>R and 2R>W aresatisfied.
 5. A developer container according to claim 3, wherein when awidth of a sandwiching opening, which is an entrance opening of saidsealing member, of said sandwiching portion is W′, a condition of thewidth W′ of the sandwiching opening is 2L<W′<W.
 6. A developer containeraccording to claim 5, wherein when a distance from a lower end of thesandwiching opening to said folded back portion of said sealing memberis D′, and a radius of an arcuate portion of said folded back portion isR, D′>R is satisfied.
 7. A developer container according to claim 5,wherein a periphery of the sandwiching opening is formed with a spongemember, and said sealing member is sandwiched by said sponge member. 8.A developer container according to claim 1, wherein said sandwichingportion is constituted by a wall, provided with the opening,constituting said frame and a part of said frame opposing said wall. 9.A developer container according to claim 1, wherein said sandwichingportion is constituted by a wall, provided with the opening,constituting said frame and a sponge member provided opposite to saidwall.
 10. A developer container according to claim 9, wherein saidsponge member is assisted by an assisting member from an opposite sidefrom a contact portion with said sealing member.
 11. A developercontainer according to claim 10, wherein said assisting member is formedwith a SUS plate and is fixed to said wall, provided with the opening,with a double side tape.
 12. A developer container according to claim 2,further comprising a filling port through which the developer is to befilled, wherein said filling port is provided on a side closer to theopening than a center of an axis of said rotatable member is, and saidfilling port is provided above a rotation locus of said rotatablemember.
 13. A developer container according to claim 1, wherein saidsandwiching portion is provided at a portion under a lower end of theopening, and said sealing member is sandwiched in said sandwichingportion so that said folded back portion is a bottom of said sandwichingportion.
 14. A developer container according to claim 13, wherein saidsandwiching portion is further provided at a portion on an upper end ofthe opening, and said sealing member is sandwiched in said sandwichingportion so that said folded back portion is a top of said sandwichingportion.
 15. A developer container according to claim 1, wherein saidsealing member includes a portion to be fixed to a part of said frame.16. A developing device comprising: a developer container according toclaim 1; and a developer carrying member for carrying the developer. 17.A process cartridge comprising: a developer container according to claim1; and a developer carrying member for carrying the developer.
 18. Animage forming apparatus for forming an image on a recording materialwith developer, said image forming apparatus comprising: a developercontainer according to claim 1.